A network architecture called “IP Multimedia Subsystem” (IMS) has been developed by the 3rd Generation Partnership Project (3GPP) as an open standard for handling multimedia services and sessions in the packet domain (for details regarding the IMS, please refer to http://www.3gpp.org/ftp/Specs/html-info/22173.htm). Various communication terminals and devices (hereinafter referred to as IMS terminals) that conform to the IMS standard are now known. A typical example of an IMS terminal is a mobile phone with IMS functionality. A personal computer (PC), a personal digital assistant (PDA), or the like can also serve as IMS terminals if they are equipped with IMS functionality. IMS terminals can provide multimedia services by, for example, receiving video streaming from a video-streaming server over an IMS network.
According to International Publication No. WO 2006/045706 which discloses a IMS gateway (IG) enabling non-IMS terminals which do not have an IMS functionality such as a desktop PC and a laptop PC to access services via the IMS network. The IG is located in a private network, to which at least one user terminal is connected. The IG can be implemented on a “Set Top Box” (STB), a “Residential Gateway” (RGw) or other home devices.
The IG enables IMS services to be delivered to a residential network where various devices such as DLNA and also sensor devices are connected. This type of IG may be called as Home IMS gateway apparatus (HIGA). The service applications are not limited to the residential network but also to a device network in car controlled by Car IMS gateway apparatus (CIGA), and also to ad-hoc or a portable network controlled by Portable IMS gateway apparatus (PIGA). The word “xIGA” represents all these different types of IG. For details regarding the xIGA, please refer to “Bringing IMS services to the DLNA Connected home”, Pervasive computing at Home WS in Sydney in May, 2008, “Virtually at home: High-performance access to personal media”, Ericsson review, Issue #2/2008 or “Beyond the Connected Car: Using the Portable IMS Gateway as an in-car Interface to Home Services”, ICT mobile summit, 2008.
PNAS (Personal Network Application Server) is an intelligent database system where device presence published by xIGA is aggregated and exposed to service providers or other types of watchers. It may also store service offering information from the service providers to expose them to home devices. PNAS has filter enforcement function so that users and the service providers can set filters to protect privacy and eliminate receiving data. In addition, it can generate statistics related to the collected information. For details regarding the PNAS, U.S. patent application Ser. No. 12/118,849 describes them.